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JavaScript Regular Expressions in JavaScript Reformatting User Input Using Replace with Captured Groups

karan Badhwar
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karan Badhwar
Web Development Techdegree Graduate 18,135 Points
Posted by karan Badhwar
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karan Badhwar
Web Development Techdegree Graduate 18,135 Points

How /(\d*)(\d{2})/ this works

For example the number is 5347 but the first part (\d*) can capture all the 4 digits, so can it just skip the Second part (\d{2}) or the whole expressions evaluates which part to distribute to which section?

1 Answer

Brian Jensen
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STAFF
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Brian Jensen
Treehouse Staff
Brian Jensen
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Brian Jensen
Treehouse Staff

Great question karan karan!

The two sets of parenthesis () are creating 2 capture groups. That way you can access the first 2 digits and the last 2 digits of that 4 digit string independently, with $1 and $2.